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Thread created as a place to post, learn, and discuss information regarding research into true ZERO black level pasma display technology. Also feel free to discuss the virtues (or not) of such technology.

PDP cells are just tiny fluorescent bulbs and just like fluorescent bulbs they have a very difficult time turning on when they have been off for any length of time. To make sure the cell can be turned off and on at high speeds in a predictable manner the cell must be primed (flooded with free electrons). To create these priming electrons every cell (all at once) undergoes a weak discharge to create priming particles once every frame. Unfortunately unwanted light is emitted which we see as black level. This all-cell discharge occurs in a step referred to as Reset or Initialization or Setup.

[Note - the Reset/Initialization step also serves the purpose of setting all pixels into a uniform low level wall charge state so that subsequent addressing of pixels properly occurs. Without a reset step it is very difficult to control the pixels on and off states. This is where the terms "reset" or "Initialize" or "Setup" come from. The pixels are set in a proper state heading into the addressing period. However, this is confusing so let us just stick to the reset vs black level problem.]

To eliminate black level completely in a PDP the all-cell reset (aka – initialization/setup) step in the driving waveform must either be eliminated completely or produce no visible light emission to the viewer.

However, without priming, the individual cells have a high probability of not discharging (misfiring). If many cells misfire then at the very least the picture will be full of black specs (called 'black noise').

Research is focusing on finding a way to generate and maintain priming without requiring any all-cell initializations or by hiding the light emitted from the all-cell initialization.

Below is a graphic that I made attempting to describe the difference between the various driving methods and how they relate to black level. The red bars represent the all-cell initialization periods each frame that generate black level. The goal is to reduce and eventually eliminate them (as in the ECC case). Note that I have normalized the number of subfields to 8 here to make things a little easier to understand. In reality Pioneer uses 14 subfields and Panasonic uses 10 (used 8 before 600Hz).

Therefore, a method of driving a PDP without generating a reset discharge has been proposed.

However, there arises a problem that, when the reset discharge is not generated, various types of the succeeding discharges are not generated in a stable manner, with increased possibility of generating erroneous discharge.

The present invention is made to solve such a problem, and has an object of providing a method of driving a plasma display panel which can improve the dark contrast without generating an erroneous discharge.

Comment – This is a confusing paper in that they discuss 3 different zero black level designs throughout the paper and then essentially conclude that they must create some black level to maintain stability??? They do this by applying a reset pulse every few frames (just like the Panasonic and Fujitsu patents)

Is it just as challenging to lower the MLL to a point where it is visually indistinguishable from "zero" black? It seems like Pioneer was quickly getting to that point with the 500m/101fd, so I wonder if something like ECC is even needed.

"Plasma TVs can display more consistent deep blacks and more movie-like images than LCDs, and they handle fast motion better, without the blur you see on many LCDs. More important, a plasma's almost unlimited viewing angle means the picture looks the same from any angle. With LCD TVs, the picture quality usually dims or washes out as you move away from dead center. Most new plasmas use no more power than a typical LCD set. We've also found that plasma TVs do better with 3D."

Quoted verbatim from the December 2010 Consumer Reports on LCD & Plasma TVs.

When any of the plasma makers come up with both the deepest and longest lasting blacks, a link would be great. Though such an occurance would be such big news on this Forum it likely would be all over the place. Meanwhile, people are buying VT20s, and VT 25s, G20s, and G25s.

Thanks everyone. Most of the info was supplied to me by you smart guys

Remember, if you find any patents or links regarding zero black feel free to post here. I really hope we get some future info.

I do realize that zero black may not be a priority to the mass market, but that does not lessen my interest in it one bit. Film content tends to have lower APL and I watch a lot of film in a theatre type setting and I find my 141 has enormous potential for black level improvement.

I just checked the IDW 2010 Program and there is not one single PDP black level submission

I made the thread a sticky. Please to keep posts focused on the tech, not current panels (unless necessary), whining about Kuro demise , Panny rising black levels, etc., stuff already said and done. Thanks.

Thanks for doing this Xrox. I also deleted some "noise" even though some of it was just "thanks", don't be offended if your post was deleted.

xrox, if Panasonic now has the ECC patent assigned to them, does it signal that they would use this technology in the future?

Is that the next step in them incorporating the tech or maybe it signals for a fact that this was a patent purchased by Panasonic--although we don't know what they purchased from Pioneer back in May 2009, since the ECC stability patents have not been assigned to Panny, I can't imagine they're trying to use it anytime soon.

It seems, from the most recent patents, that Panasonic is not going in that direction for 2011, but slowly working their way to an EC display- stability issues being countered by using it in a 50/66% mix of their zero black drive with their conventional driving method.

If 10 lumens/watt are achieved in the next year or two, wasn't that alone, enough to allow blacks to go near zero?

xrox, if Panasonic now has the ECC patent assigned to them, does it signal that they would use this technology in the future?

Is that the next step in them incorporating the tech or maybe it signals for a fact that this was a patent purchased by Panasonic--although we don't know what they purchased from Pioneer back in May 2009, since the ECC stability patents have not been assigned to Panny, I can't imagine they're trying to use it anytime soon.

The assignee change to Panasonic only signals that they purchased rights to it before it was issued AFAIK. One could only speculate on intent to use.

I'm no expert in patent law but AFAIK what happens after IP purchase is that assignee name changes to the purchaser name only on future issued patents. Applications or current issued patents retain origninal name.

Quote:

Originally Posted by gmarceau

It seems, from the most recent patents, that Panasonic is not going in that direction for 2011, but slowly working their way to an EC display- stability issues being countered by using it in a 50/66% mix of their zero black drive with their conventional driving method.

That is assuming they are even going to use that technology in 2011. D-Nice is the man to talk to about what it actually being planned.

Quote:

Originally Posted by gmarceau

If 10 lumens/watt are achieved in the next year or two, wasn't that alone, enough to allow blacks to go near zero?

There are many ways to improve efficiency in PDP and not all of them enable improvements in black level. Cell improvements that target long lasting priming (such as the KURO) directly enable black level reduction as well as efficiency improvement.

I think of it this way. KURO was a dramatic improvement in long lasting priming and even KURO could not stably produce ECC without extra priming (patent app#20090002276) so how could current Panasonic designs hope to do so.

thats just f'n great. panny buys out pio tech and holds it hostage. the result is the best leading mll up to 1500hrs. most consumers arent aware of this, resulting in panny taking the crown and those of us who do the research can only turn to flipping samsung! what has this world come too? if panny actually cared, we'd be owning pio tech sets this year and looking at ecc tech sets within two years. and what do we get? sets worthy of a recall from panny and sammy trailing behind with tech not advancing in three years counting. i had my kuro stolen this week. and my hoeowners is asking me what current panel is an adequate replacement. i'd say give me the dough in throw up bags, because the advancement of non niche market plasmas has gone dry as a bone in the past 2 years. frick 3d.

Apart from Panasonic no other Plasma brand has ever been tested for long term black levels. I have no doubt other brands won't have the MLL rise to the same extent as Panasonic but I'm sure the panel will change for the worse. Either with a small MLL rise or a better MLL with worse shadow detailing.

I am fascinated that Panasonic would even consider this method. I may be totally off base but it appears that this would reduce the pixel pitch (aperture) by at least 30%. Wouldn't this reduce panel efficiency? Can Panasonic afford this amount of reduction with the market push towards power reduction?

I am fascinated that Panasonic would even consider this method. I may be totally off base but it appears that this would reduce the pixel pitch (aperture) by at least 30%. Wouldn't this reduce panel efficiency? Can Panasonic afford this amount of reduction with the market push towards power reduction?

-Matt

Hi Matt,

That is a very good question. The separate cell for priming has two (maybe 3) benefits.

1 - reduction in black level by blocking some or all of the light from initialization

2 - increasing addressing speed by reducing the discharge delay

3 - Another 'possible' benefit this may produce is to stabilize the black level over usage time (no more rising blacks) because the MgO layer in the phosphor subpixel would be under less stress.

#2 essentially increases efficiency by reducing the time needed for addressing and increasing the time available for light emission (sustaining). But as you say the reduction in arpeture will reduce the brightness. So maybe they offset each other?

After reading the Panasonic paper thoroughly I now see why they don't mention black level. It seems they intend to use the separate cell as an auxiliary priming source and still keep priming inside the phosphor subpixel as well. They are trying to maximize benefit #2 (above) in order to achieve 4K resolution and high speed addressing for 3D (120Hz).

Even so they still could achieve zero black by doing all-cell initialization in the separate priming cell and doing selective initialization in the phosphor subpixel.

Another issue is the actual colour of the display itself. Not just the light emitting from it. The plasma displays tend to be a kind of dark greenish grey even when unlit (But lit from the front by either natural or unatural light). I.E. the panel itself has a certain amount of reflectivity and I am not just referring to the glass refelectivity. It's not a true black panel. CRT's were never pure black either. If the display could somehow match the blackness of the bezel...

Another issue is the actual colour of the display itself. Not just the light emitting from it. The plasma displays tend to be a kind of dark greenish grey even when unlit (But lit from the front by either natural or unatural light). I.E. the panel itself has a certain amount of reflectivity and I am not just referring to the glass refelectivity. It's not a true black panel. CRT's were never pure black either. If the display could somehow match the blackness of the bezel...

Maybe I am just being picky here.

A separate topic but a good one. And no you are not being picky. A zero MLL combined with a dramatic improvement in AR filter tech would be ideal.

An expensive option would be to use individual color filters in each subpixel but it would work IMO. Anyway, that is for another thread

The assignee change to Panasonic only signals that they purchased rights to it before it was issued AFAIK. One could only speculate on intent to use.

I'm no expert in patent law but AFAIK what happens after IP purchase is that assignee name changes to the purchaser name only on future issued patents. Applications or current issued patents retain origninal name.

The assignee listed on the face of the patent only indicates the assignee at the time the patent issues (as listed by the one paying the issue fee). However, a patent (or published application) can be assigned post issue (or post publication), and usually the assignment is recorded at the USPTO, but it will not be updated on the face of the patent (or publication) itself. So, patents assigned to Pioneer at issue and later assigned to Panasonic will not show this info on the face of the patent.

Apart from Panasonic no other Plasma brand has ever been tested for long term black levels. I have no doubt other brands won't have the MLL rise to the same extent as Panasonic but I'm sure the panel will change for the worse. Either with a small MLL rise or a better MLL with worse shadow detailing.

Kuros do not rise --- Samsung do not rise --- LG do not rise. While their is a patent for Panasonic describing rising black levels. Nor do they have that great feature that Panasonic has 'floating blacks'. It was a great feature that I wanted to hit my Panny 50v2oa with a cricket bat, but I got rid of the TV. Now I'm stress free

Another issue is the actual colour of the display itself. Not just the light emitting from it. The plasma displays tend to be a kind of dark greenish grey even when unlit (But lit from the front by either natural or unatural light). I.E. the panel itself has a certain amount of reflectivity and I am not just referring to the glass refelectivity. It's not a true black panel. CRT's were never pure black either. If the display could somehow match the blackness of the bezel...

Maybe I am just being picky here.

Is it just me but somehow I do find my kuro screen turns darker when it is on vs the greenish grey that you mention when it is off for some time? If true any logic on this?